The present invention relates to a process for expanding a tobacco material, and more particularly to a process for increasing the filling power of a tobacco material.
When tobacco material is processed for use as cut filler for the manufacture of cigarettes, the density of that material increases relative to the density of that material in a natural condition. Thus, processed tobacco material used in cigarette manufacture often has a density greater than necessary for producing acceptable cigarettes. There have been proposed various processes for reducing the density of processed tobacco materials in order to reduce the weight of tobacco material employed in manufacturing each cigarette. See, for example, the various tobacco expansion processes described in U.S. Pat. Nos. 3,524,451 (Re. 30,693) to Fredrickson; 3,524,452 to Moser et al; 3,683,937 to Fredrickson et al; 3,771,533 to Armstrong; 4,235,250 to Utsch; 4,258,729 to de la Burde et al; 4,336,814 (Re. 32,014) to Sykes et al; 4,340,073 (Re. 32,013) to de la Burde et al; 4,531,529 to White et al; 4,574,819 to Rainer et al; 4,366,824 to Rainer et al; 4,459,100 to de la Burde et al; 4,641,655 to Hedge et al and 4,696,313 to Brown et al.
Expanded processed tobacco materials have densities which are reduced and filling powers which are increased relative to similarly processed tobacco materials which have not been subjected to an expansion process. By "filling power" is meant the ability of a smokable filler material, at a particular moisture level and temperature, to form a firm smokable rod for a cigarette. Methods of determining the filling power of tobacco materials are set forth in Tobacco Encyclopedia, edited by Voges, p. 457, TJI (1984).
It would be highly desirable to provide a process for expanding a tobacco material in order to increase, to a very high degree, the filling power of that material.